During metal/copper chemical mechanical polishing processes, three films/materials are encountered. 1) A patterned dielectric layer, usually silicon oxide (oxide), within which an opening is formed; 2) a barrier layer which lines the oxide layer opening and covers the top of the patterned oxide layer; and 3) a metal layer, usually copper, formed over the patterned dielectric layer, filling the barrier lined opening. In order to planarize, or polish, the metal layer to form a planarized metal structure within the barrier lined opening in the dielectric layer, a variety of polishing steps with various slurries are employed.
U.S. Pat. No. 6,217,416 B1 to Kaufman describes a first and second CMP slurry wherein the second slurry includes an abrasive, an oxidizing agent and acetic acid wherein the weight ratio of oxidizing agent/acetic agent is at least 10 and wherein the two slurries are sequentially used in a method to polish a substrate containing copper and containing tantalum or tantalum oxide or both tantalum and tantalum oxide.
U.S. Pat. No. 6,338,744 B1 to Tateyama et al. describe a high purity polishing slurry comprising water and dispersed silica particles.
U.S. Pat. No. 6,261,158 B1 to Holland et al. describes a multi-step CMP system used to polish a wafer to form metal interconnects in a dielectric layer upon which barrier and metal layers have been formed.
U.S. Pat. No. 6,447,371 B2 to Brusic Kaufman et al. describes a chemical mechanical polishing slurry useful for copper/tantalum substrates.
U.S. Pat. No. 6,313,039 B1 to Small et al. describes a chemical mechanical polishing composition and process.
U.S. Pat. No. 6,530,968 B2 to Tsuchiya et al. describes a chemical mechanical polishing slurry.